1. Technical Field
The present invention relates to an optical rotation measurement method for measuring optical rotation, and the like.
2. Related Art
The components of a substance can be known by utilizing properties such as the absorption, scattering and optical rotation of light by the substance, without directly contacting the substance. For example, measuring optical rotation enables the density of a substance to be estimated (calculated). Optical rotation is a property according to which the polarization plane rotates when linear polarized light passes through an optically active substance such as glucose, for example. Another known technology involves, for example, measuring the components of a living body by irradiating the living body with near-infrared light and acquiring the spectral characteristics of scattered light and transmitted light from reflected light that is received (refer to JP-A-2008-309707).
Generally, reflective optical measurement is performed by causing measurement light to be incident perpendicularly on the surface of a subject and receiving the reflected light such as with the technology of JP-A-2008-309707. However, it is considered difficult to measure optical rotation with a configuration that measures reflected light that is reflected in the same direction as the incident direction. This is because the optical rotation that occurs in the process of light being propagated in the incident direction is cancelled out in the process of the reflected light being propagated in the opposite direction to the incident direction.